Trimbw



March 6, 1928.

N. A. ROBINSON SIGNALING SYSTEM Filed March 1927 5 Sheets$heet 4 Z w Rmm OZ. E m m Eamwo W Y B WITNESSES a /r fl Marchfi, 1928. 1,661,962

N. A. ROBINSON SIGNALING SYSTEM filed Marph 1927 5 Sheets-$heet 5 lllllllllll IIIII INVENTOR ATTORNEYS Patented Mar. 6, 1928.

INILS A. ROBINSON, NEW .YORK, N. Y.

Application filed March 14, 1927. Seria1'No. 175,313.

This invention relates to signaling sys SIGNALING SYSTEM.

tems. and more particularly to wireless telegraph systems, and is especially adapted for use in printing telegraph systems.

The object of this invention printing telegraph apparatus.

Another object is a system of wireless signaling inconjunction with the standard printing telegraph apparatus at present in use.

' Another object is a system capable of operation at higher speed'than the systems of the prior art.

is an improved system of signaling wlth standard Another object of the invention is simplicity of construction.

Another object is reliability in operation. Another object is an inexpensive system.

In accordance with this invention means is provided for generating a plurality of alternating currents of different frequencies, these frequencies, preferablytwelve inall, being used in various combinations in accordance with the particular combination'of frequencies representing the particular character to be transmitted, means being likewise provided to translate each frequency combi-' nation into its components so as to indicate the particular character or symbol corresponding thereto.

In a signaling system tlre'employment of 12 distinct divided into two groups. one group repre sented by thefirstimpulse and comprising eight distinct frequencies. and the other group representedjby the second impulse and comprising four distinct frequencies. l:

of this character it is usual to employ 32 symbols or char' acters. This necessarily requires 32 different signaling combinations. In one form of my invention I obtain these 32 combinations by frequencies,

thus employ a total of twelve distinct 'fre quencies in the operation of my system.

In the drawings comprising five sheets. Figures 1 to 7 inclusive) the invention is diagrammatically set forth as a wireless signaling-system.

pplied t a 1 discloses the equipment at the transmitting station.

' Fig. 2 discloses the equipment at the receiving stationa Fig. 3 discloses an alternative form of equipment used'in a modification of the 'system of the transmitting'station shown in Fig. 1. I

Fig. 4 discloses a modified form of equipmentto be used at a receiving station designedto operate in conjunction with the transmitting station disclosed in Fig. 3.

Fig. 5 discloses a suitable form of oscillator for use with Fig. l or 3. I

Fig. 6 discloses a suitable form. of radio transmitter for usewith Fig. for 3.

Fig. 7 discloses a suitable form of radio receiver'for use with Fig.2 or 4.

Certain elements of Figs. 1 to 4:, inclusive,

are shown dotted. These elements are used forthe purpose of obtaining a greater- 'number of signal combinations than thirty-two. It should be distinctly.understood, however.

that in the following description they are 1 assumed not to be used unless specifically referred to. I

Referring to Fig. 1,.TT represents a tape transmitter machine or other device wherein the five contact members 1 to 5 are capable of simultaneously assuming one of two positions,lwhich we will designate left or right against the corresponding left or right contact. Such a mechanism readily unit code. One form of tape transmitter machine suited to this purpose is described and illustrated in the publication entitled Printing Telegraph Systems and Mechanisms by H. H. Harrison, first editionprint edby Longmans Green (10;, London 1923.-

See particularly Fig. 179 on page 179;

LN. designates an impedance networlr capable of producing in conjunction with the oscillator. any one of a series of twelve different frequencies dependent uponthe par? ticular contact member or members 1 to 5 Y which may be closed against the eerrespend c 80 lends itself for use in connection with a five of the interrupter 6.

ing left contact to complete a network of a certain impedance.

It is, of course, obvious that the resulting impedance of the entire network I. N. in bridge with the oscillator at leads 8 and 9, will be dependent entirely upon the setting of the contact members 1 to 5 inclusive. The device (3 is an interrupter of any suit able form whose cycle of operations 'consists in alternateh closin -its lower contact 26- while opening its upper contact 16 and then opening its lower contact 26 while closing the upper contact 16.

The magn' t 7 advances the tape afteri:

the completi n of each cycle of operations The oscillator may be of any desired type so long a-sit is 'c ap'able' in conjunctienwith the impedance network 1. of gener'atingany one of the desired and predetermined group of frequencies. One suitable'forinof oscillator isdescribed and disclosed in Prin ciples f Radio Communication "by J.'H. Morecroft, first edition;published by John Viley & Sons, New York 1921.55ee partic ularlyFigure l09 at page $88. The oscillator of 109 of More'croft should be modilied to coiiforin-to the circuit arrangement shown inFig. 5liereofg A The radio transmitter maybe of any desociated with in operating in accordance with the 5-unit code may be employed as the machine TT. The transmitter tape will be perforated to represent t-he particular symbol or character which it is desired to transmit and these perforations will be in alignment with a series of live reciprocating pins, not shown the position of each pin controlling the position :of each'one' ofithe-contact'inembersl to 5,

inclusive, with reference to the particular one of contacts 11 to 15, inclusive, that is as- Therefore, as the tape moves pastthe pins, one or more parallel circuits; comprising the impedance network I. N. will be closed in order to prepare a circuit in accordance with the perforations in the tape. At the same time the interrupter 6 will commence its cycle of operations preparatory to-transmitting the first pulse of the desired code and to that end a circuit will be completed to the oscillator across the leads 8' and 9 and including illGJllitGlIUlJiQl 6 and its associated lower contact The circuit thus established will complete a paricular impedance networlc coinprisingnet- -work 31and generally one or'more of net- "works 33-to 35, inclusivex sired form. A suitable form of transmitter is shown in the publication entitled The Thermionic Vacuum Tube and Its A'p'plications -"by' HIATFV an der-Bij'hiir'st edition,-

published by McGraivHill; New York" 1920,

partieularlyat' page 32% Figf'193 described on pages 323 and 824 thereof. The trans-' nitter c'ir'cuit' of Van der Bijl if used is modifiedliowever' to conform to the circuit arrangement shown inFi'g. 6 of the draw ings hereof.

The apparatus *at the receiving station is" illustrated in Fig. 2. The radio receiver represented the rectangle maybe of'any.

desired form such'fo'r example asthat shown in the publication The ThermionicVacuum Tube'and Its Applications by H. J.- Van der "that the various 'pedance netwerk T. N.-

erated in the oscillator will Bijl heretofore referred to particularly at pages 332 to' 835 inclusive, and especially Fig. I98 at'page332, and-may include ainlifiers in instance of that e described on 11 to 15,- pages 258 211(1254: of said publication. The

circuits of-Van 'der Bijlif used shouidbe" modified however to conform to the circuit arrangement shown'in Fig.7 ofth e draw ings herein. V

The system of Figs. land 2 functionsas sistance of the impedance network follows: The transmitter tape, not shown, is"

carried forward stepby stepby mechanism; not shown; controlledby the magnet; As

the tape-transmittermachine forms no part of the present invention and is well known in the art it will not be-described in detailw Any standard tape transmitter machine Referring to Figs. 5 and 6, it will be ob served that closinganilmpedance network in bridgeacrossithe leads 8 and 9 in the manner previously described will complete circuit lIl'ClUClll'lg'tllG primarywinding-631 ot the transformer 630, plate 504 and filament one orniore of these:

is into or disconnected from the circuit by the opening orclosingunder control of: the

tr nsmittertape of any of the contact members 1 to Grind-their respective contacts ance ofthe l pedance-network will result in the generation of an alternatiiie' current of a particular freouency. Tlie frequency of "every other current generated as a result of every other value of the effective rel. N. will be readily detectableand distinguis iable one from another atthe receiving station (Fig.

Referring;to, Fig. 6 it will be observed that the tubes 600 and 610 and their asso-V oiatedapparatusand wiring are arranged to oscillate at a predetermined radio frequency Each value of-tlie effective resistfrom the aerial 620. As the alternating cur fJl relatively short period of time.

so that an alternating current of a particular radio frequency will constantly emanate rent generated by the oscillator (Fig. 5) is superimposed upon the alternating current of radio frequency generated by the radio transmitter due to the inductive relation between the windings 631 and 632 of the transformer 630 the alternating current of radio frequency will be modulated by this alter nat-ing current superimposedfrom the oscillator circuit so that whenever a circuit for the impedance network I. N. is completed by way of the interrupter 6 and in general one or more of the contact members 1 to 5, inclusive, the alternating current of radio frequency will be modulated by the alternating current generated in the oscillator circuit (Fig. 5). v a

As has been previously stated each symbol or character transmitted by the tape transmitter TT requires two pulses. The first pulse having been transmitted by the radiation of the modulated radio frequency cur rent from the aerial 620, we are now ready to obtain the setting for the second pulse and to transmit the same.

As previously indicated, the interrupter 6 may be of any preferred form. Frequently a tuning fork is used, although the form of interrupter is not; important so long as itis reliable and travels at a-substantially constant speed. The interrupter should be so designed that the member 6 will make contact with either 16 or 26 for relativelylong periods of time, and so that the transfer period from one contact to the'other will be a to transmit the second impulse it isnecessary to break the circuit across the leads 8 andy9 at the interrupter contact 26 and to make Contact bet-ween the interrupter 6 and its contact 16 to introduce a ne v and different impedance network in bridge across" the leads 8 and This'network will comprise network 32 and generally one or both of'net works 36 and 37. The change in the effective resistance of-the impedance network results in the generation of an alternating current of a characteristically different frequencyin the oscillator Fi 5, and this in turn results in the characteristically different modulation of the alternating current of radio frequency emanating from the aerial 620. Having transmitted both pulses corresponding to the specific character or symbol indicated by perforations in the transmitter tape we are" now ready to advance thetape transmitter in order to transmit signals C011".

responding to the next symbol or character. At the time contact 16 of interrupter 6 was closed a local circuit was completed for the electro-magnet 7 and when the interrupter 6 having completed its cycle of operations 'tions, namely, open and closed, as

In order I from amere inspection of Fig.- ment 711, grid 712 and plate 713 of tube 71.0

commences a new cycle contact 16 is again opened at which timethe electro-magnet 7 releases to advance the transmitter tape preparatory to sending pulses corresponding to the next character or symbolindicated by that the contacts 11, 12 and 13 of the con tact members l, 2 and 8 are controlled by contact 26 of the interrupter 6, and as each of these contact members has two positions, namelyflopenl or closed it is obvious that the contact members 1, 2 and 3 maybe set to produce two times two times two, or eight diflerent combinations. .Similarly contacts 14: and 15 of contact members 1 and 5 are controlled by the contact 16 of the inter rupter 6 during the sending of the second pulse of any particular character. lhese two contact members likewise have two posia result whereof it is possible to obtain two times two, or four different combinations during the transmission of the second pulse of the cycle. Each of the eight combinations of the first impulse. of the cycle may, there. fore, be combined with any one of thefour,

or thirty-two different possible combinations of impulses are available which may be utilized to transmit'anyone of, thirtytwo different characters or symbols.

' The signal emanating from'the aerial 6'2 at the transmittingstation (see Figs. 1 and 6),-is received in the aerial 700at the re I ceiving station (see Figs. 2 and 7). Referring to Fig. 7, the signal thus received in the aerial 700 flows through the primary winding 7 02 of the transformer 701 and a-current of like characteristics is induced in ti secondary winding 7 03 of the transform is, of course, understood that thiscircuit is tuned to} the radio frequency of the tr 1 mitting station (Fig.1);

In accordance with well known principles the tube710 functions as a detector to detect the audio frequency.

the lil aare wired in accordance'with the usual aris obvious ltlU rangemcnt fora vacuuln tube detector and he audio frequency'thus detected is conducted through two stages of amplification by means of tubes 720 and 7 30 and the associated wiring so that at leads 745i and 74:2

the audio frequencyhas been amplified many fold.

Referringv to Fig. 2 it will be observed that the audio frequency thus amplified passes through the primaryi vindings of a series of a group of twelve transformers which are connected in series. 10111 7 one of these transformers jto wit: transformer izOO is shown in detail, itibeing understood that the other eleven transformers which are merely indicated by eleven squares are simi lar in all respects to transformer 200.

The current of audio frequency flowing in the primary winding 201 results in the generation by induction of la eu'rrentof similar characteristics in the secondary winding 202 of transforme1'i200. The vacuum tubes 210 and 220 which are connected i rtandeinj form part of a system including the condenser/ 205 and (when sw tch-2M is closed) the resistance 1203, which is tuned toone of the twelve audio frequencieswhich are em-' either the up or down positiondependentf upon the direction of themagnetie field gen erated by the last currentfiowing through the winding or windings of the polarized relay or relays Y 7 Relays 260, 270 and 280 may or may not be polarized, but these relays,- is indi cated in Fig. 2 of the drawings, are all bifl used in such a manner that inthe normal position of these relays their respective armatures 269, 279 and 289 rest upon their respective back contacts; The'inag nets 290'to:

295 inclusive are the printer magnets which.

are utilized to record or indicate 'eithei au dibly or visibly as desired, the sy nb'ohor character. corresponding to the signal received at, the receiving station which, turn, corresponds to the symbol or character transmitted by the transmitting station, Fig.1., i i

Each of the relays 230,2;0 and 25Q provided with six windings l' These windings reading from the left willb ereferred to as windings 1, 2, 8, 1, 5 andf6 respectively. To avoid the unnecessary multiplication'of characters on the drawings, individual reference numerals have (not been' applied to each of these windings.

Relays 2 and 27 0 are provided with two windings which reading from left te right This will be, referred to as windings 1 and 2.

"Relay 280 is provided with three windings which reading from left 'to right will be re- V ferred to as windings 1, 2 and 3respectively. Relays 230, 2410 and 250 are utilized'for the purpose of recording the first pulse of any character or symbol transmitted at the transmitting station Fi 2'under controlof the interrupter 6. Relays 260, 270 and 280 are utilized for recording the signal'transin'itted in accoresncewith' the second pulse of any particular character or symbol. will be observed that the various windings of relays 230, 24:0 and 250 are connected by means of the leads 207, 217, 227, 237, 2 17,

' 257, 267 and 27 7 to the tuned systems associated with the first eight transformers in" the group of twelve transformers indicated "by the transformer 200 and the series of elevensquares at the left of Fig, 2. It will also be observed that thewindings of the relays 260, 270 and 280 are connected by means of the leads 296, 297, 298 and 299 to the tuned systems associated with the remaining four transformers of Fig. 2. Obviously, therefore, any one of the groupof twelve p'redetermmed frequencies emanating from the aerial 620 of Figs. land 6 will'be detected and amplified in'the radio receiver (Fig. 7 and conveyed thence by a'lead 74:1 and 742 to the group of twelve transformers in series. The one of the twelve rectifier circuits which is tuned to tliat specific frequency will thereupon function to 'rectify the same and convey the rectified current via one of the leads 207, 217, 227, 237,247, 257,

267, or 277, if the current representsthe first half cycle of the interrupter 6 (Fig. 1) or via 'one of the leads 296, 297, 298 or 299 if the current represents the frequency generated during the second half cycle of the interrupter 6 (Fig. 1), to the proper group of relays, which, as heretofore indicated, will either the upper group, if the currentrepresents the frequency generated during the first half cycle, or the lower group it the current representsthe frequency generated during the second half cycle of the inter rupter 6, said current flowing back to the rectifier clrcult by way of the common lead. 206. Dependent upon the dlrectlonsof thoseof their windings traversed by the current, the various relays will assume various settings corresponding to the'particular characteror current.

The following is a typical code which might be used at the transmitting station,

-Fig. 1, and the receiving station, Fig; 2, for

the purpose of transmittingand receiving the various'frequencies It will of course be understood that the manner of combining any one of the first eight frequencies designated 1 to8, wlth any one of the :Fc-ur symbol represented by the signal material to this code.

'- Transmitter tape i Relay setting Frequency 0 o 0 D D U C O O U D U G O O U D D O C O U U' D O O .O D U U 0 O O D U D O C G U U U 0 O O D D D O O U D O O U U 0 C D U 0 O D D The symbols C and 0 applied in the tabu lations of the transmitter tape are intended to indicate closed or open respectively,

with respect to the five contact members 1.

to 5, inclusive, and the symbols U and D applied to the column relay setting, are intended to indicate theoperated position and the down, or released position of the relays 230, sec, 250,260 and 270, respectively. It

is assumed that the tuned circuits associated with leads 207, 217, 227, 237, 247, 257, 267, 277, 296, 297, 298, 299, individually respond to the frequencies designated 1, 2, 3, respectively, in the above code.

it is obvious that as soon as the second impulse is being received, relays 230, 240,

250, 260, 270 will have assumed settings idenlays 260 and 270. lhe relative slowness of 280 is 'desirable in order to permitrelays 260 and 270, if operated, to close their respective armatures and front contacts to complete circuits for their respectiverecorder magnets 293 and 294 before relay 280 has an opportunity to operate andcornplete the circuit via its armature-289 and front contact, for the magnet 295. The function of magnet 295 is'to start the recording or pr nting of a character at the receiving station.

it will be understood that magnets 290 to 294, together with magnet 295, are a part of the recording device and that their sole function is to-control in said recording de rice, the utilization of the received five-unit signal combination for printing of a letter, or for giving visible or audible indication, or for performing any other selective operation that. may be desired.

It should be understood that the number of symbols which the system disclosed in Figs. 1 and 2 is capable of transmitting may be increased by adding an additional set of contacts in the tape transmitter machine .lT (Fig. 1) so as to employ a six-unit instead of a fiveunit code. To effect this modification, the elements shown dotted in Figs.

1 and 2 are added. lrnothercircuit, 38 (Fi '1), comprising inductance and capacity, is

added to the impedanceenetwork I. N. to operate in conpinot on With theextra contact. By connecting this additional circuit across contact; 16 and lead 8 as shown, and by adopting a six-unit code Which has the sixth element operated only for eight combinations, these eight combinations having Qtheir fourth and fifth elements not operated, it is obviously possible to transmit eight times five or forty combinations by the use of eight plus five or thirteen frequencies. It will, of course, be understood that this modification will necessitate a change in the receiving arrangement, as shown in Fig. 2,

toinclude another tuned circuit, associated With lead 273, another Winding on relay 280, another relay 275 of the type of relays 260 and 270 but with one Winding, and another recording magnet 274 of the type of magnets 290 to 294, inclusive.

The following code, might be used With the above arrangement.

Transmitter taper. Relay setting Frequency 2 p O O C D D U C O C U D U C O O U D D C O O U U D 0 C l O D U U O C v O D U D G G C U U 'U 0 O 0 D D D C O O U D D C C O U U D o o o D U D O I O O D D D O O O D D i U The symbols C and 0 refer, of course, to 1 the respective closed and open-positions er the six transmitter contacts 1, 2, 3, 4,

5 and 17, While the symbols need D signify the up? and down positions, respec tively, of the various relay armatures.

Figures 3 and4 of the drawings disclose an alternative system for that disclosed in Figs- 1 and 2, heretofore described.

The oscillator(Fig. 5) may be used at he point designated oscillatorin Flg. 3,

and the radiotransmitter (Fig. '6) may be used in conjunction With the oscillator (F1 2 5) at the point designatedradio transmitter, in Fig. 3.

-.The radio receiver (Fig. 7) may be used ,in conjunction with the -receiving-system radio receiver; Whereas-the system disclosed 1n F1gS.1'

disclosed in Fig. 4 at the and 2 constitutes a system-having two imwherein each character or symbol is; trans nut-ted by a signalv combination comprlslng :three separate successively transmitted impulses- P f :Inthesystem disclosed-in Figs. 3 :and 4:, and referring; more specifically to iFig. 3,

the tape transmitter machine is indicated at T -F- and the impedance networkat I. N.

ItQCODSlStS, in the form shown, -of acomm'u- .se'gments'301 to 306, inclusive. The brush O is adapted to bridge the I segments of the commutator to the feed bar -or slip ring,-thereby momentarily closing the feed bar or slip ring 308 tothepairs of segments 301, 304; 302, 305; and 303, 306-; in succession.

"The commutatorend feed bar 303 -in the preferred form constitutesa. drum or interrupter rotating at-suitable speed under con-..

. ,pe riod,. which willibe relatively short.

,trol of an electric motor or some other source of ClI'lVlIlg power. Itw1l1-be observed that the segments 301 to 306,incl usive, are.

relatively long as compared jwitlltllfiinsula- .long as compared-with the open circuit The general principle ofnoperation of similar to thatofthe systQnsQtiOrfih in W Figs; 1 and 2. It should be understood ho\vever,.;.tl;1at with the [system of Figs. .3

and 4-, itispossible to obtainthirty-two signed for forty-eight combinations of im- -,.pulses,'that is,',,for transmitting fortyeeight,

U i combinations when fivesets of contacts (310 to- 314:,inclusive) are used, .and forty-eightv combinations when siX sets of contacts (310 ..to .315 inclusive) are. ,used. [The circuit .wiring indicated in dotted lines in Figs. .3 andisonly usedwhen the system is decharacters or symbols. I Inthe system of Figs. 3 and onlysix.

' frequencies are ordinarily. used. Whenthe sixth set otcontacts 31 5, 325 are used, the

number of frequencies is increased to seven. It is, therefore, obvious that the system of point designatedtatonor interrupter drum comprising a: -feed bar or shp'rmg 308 and a series of and reduces .thenumber of frequencies employed: but increases the number ofimpulses per cycle. Itwillbe understood,

.therei'ore, that due to. the increase 1n the number otimpulses per cycle. from two to three, the system of Figs. 3 and a Will be somewhat slower; in operation-than the system of Figs. 1 and 2. At..the,commencement otthe cycle, that-,is, iw hen the first impulse of a signal, combination correspond ing: to a-character is about tobe transmitted, the brush 300 will ;be inap osition to connectsegments 301 and304 of the commutator to the feed bar or slip, ring 308. Duringthe transmission-"ofthe second impulse ofjthe cycle, the brush 300ovillbe. in a position; to connect segment; 3020f the commutator itothe feed bar or slipn ing 308.- Similarly, when the final or'third impulseofthe cycle. is. transmitted, the brush 300 Will bridgethezi'eed banor slipa'ing. 308 to segments303 and 30.6. Itthusappears that if the commutator is in.the formof an interrupter. drum, said. drum must rotate in a.

clockwise direction,.whileif it is in the form of. a flatycommutator providedqvith a moving brush, the brush must move from left to rig-ht.

It will be understoodlthatldependent upon- ;thepunchings in the transmitter tape, the .mechanism controlling the .contact members 310 to -315, inclusive, and their associated forward-contacts 320 to 1 3.25,, inclusive, will cause onenor more,.o r none, of these contact membersand .theirassociated forward contactsto be.closed, thus ,varying the impedance of ,theimpedance network I. N. con- 'nectedin.- bridge across the conductors 8 tion between the various pairs'of segments,.- 30-1, 30%; 302, 305.; and.303,-306.-- As a re-. sult, ;the period of-closure from the feed bar or slip'ring- 308-via --the brush 300 to the: various pairs of segments will be relatively.-

..witli.;.respect-i.to brush 300, theimpedance of.tl1e. networkI.,N. will assume a different value in..accor'clance with ,thefsetting of the contact members and their associated coni V tacts...,.As..a1 result of this operation, there ithe system setforth 1n Figs.3-and 4 is.

will be a combination of three successive 1mfrequencies.;-..The frequencies will modu- .late-tl1e; 1:adi0. Wa-ve emanating from aerial .620. as heretofore described.

. The receivingaerial -0 (Fig.4) pick up this modulatediradiowave and the same will be detected and its characteristic frequency amplified in the radio. receiver (Fig.

.7).. This frequency will be impressed on .the prnnary wind ngs, n ser1es,.of transformers 400 t0406, inclusive, by way of leadsML and 742. It-will be understood thatthe, secondary winding408 of the transformer 400 and the secondary windings of eachof the transformers lO lto 406, inclusive, are eachindividually connected to a tuned circuit comprising a rectifier, the arrun rangement indicated in conjunction with the transformer 400 being typical. As each of thesetuned circuits is substantially responsive to but one particular frequency, and as the transmitting arrangement heretofore described is only capable of transmitting one frequency at a time, it will be seen that at any given time only one of said tuned circuits will operate. 1

Referring to'F 4, relays 450,455, 460, 465, 470, 475, 480 and 482, are polarized but are not biased. Relay 484 may or may not be polarized but this relay is biased so that in its normal position the armature ofrelay 484 rests againstthe back contact of the relay.

' unit code. The former case will be considered first, i. e;., in the description immediately following, all dotted elements of Figs. 3

and 4 will be disregarded.

When the tape transmitter T-T (Fig.3)

is ready to transmit the first impulse of the cycle, the impedance network I. N. will be. closed via 8, 316, and 326 in parallel, 327, and 329 to 9. This impedance may be modified by way of a parallel path through 310,' 320; or 311, 321; or both; and 301 or 304, or

both, to 307; 329 toIle-ad 9.: One of four frequencieswill be transmitted from the aerial.

620. One of the rectifier circuits connected to the secondary of one of the transformers 400 to 403, inclusive (Fig. 4) is tuned to respond to the frequency transmitted. Relays 450,455 and 460 will now assume a setting dependent upon the frequency transmitter so thatv armatures 452, 457 will rest either against their front contacts 451, 456, or against their back contacts 453,458. Relay armature 462 will move up against its front contact 461. I i

That this Will be the case for all four fre quencies is evident from the fact that the left-hand Winding of relay 460 is included in all four circuits. The directions of the windings are assumed to be such as to cause armature 462 to move as described. I

Relays 480 and 482 will assume the same setting as relays 450 and 455 in the following manner. Relay 480 operates as'follows: from battery, lead B O, right hand winding 480, back contact 468 and armature. 467 to battery. If relay 450 is not operated, however, there is a circuit through the left-hand winding of relay 480 as follows: battery,

lead B O, 452, 453, left hand Winding relay 480, back contact 468 and armature 467 to battery. Owing to the differential condition inclusive.

through its windings in parallel relay 480 will not'operate at this time, but itsarmature will be forced against'its back contact. It is obvious,'however, that whenever relay v450 operates thereby removing the differential condition relay 480 will operate through its right hand Winding over the local circuit traced, causing its armature to more up againstits front contact 481. Relay 482 functions similarly to relay 480 over circuits through its windings in parallel, the left hand winding of relay 482 being controlled by relay 455.

During the second impulse of the cycle, brush 300 (Fig. 3) bridges 308 to 302. It is evident that the transmitted frequency is under control of contacts 312, 322. One of twofrequencies will be transmitted. To this frequency a tuned circuit connected to transformer 404 or 405, also relays 470, 460 and 465 (Fig. 4) respond to assume a setting for the second impulse. More particularly, 470

may or may not operate, armature 460 of 462 will release, pressing against its back contact, and relay 465 will operate. The operation of relay 465 opens all. circuits through the windings ofrelays 480 and 482 at its armature 467 and back contact 468. Relays 480 and 482 being polarized do not change theirformer setting.

During the third. and linal impulse, the

impedance of the network I. N. (Fig. is.

controlled bythe contact members 313, 323;

and 314, 324 brush 300,-segments 303 and 306,'and slip ring or feed bar 308. One of four frequencies will be transmitted. It is:

evident that the four frequencies that are applicable to the third impulse are the same that were availablefor the first" impulse.

At the same time the magnet 328 controlling the advance of the transmitter tape is energized via 306. When this magnet releases upon the open1ng of the circuit formerly closed by way of segment 306the tape is advanced to the nextposition in the tapetransmitter machine T- T. a

Relays 450 and 455 again assume asetting and, relay 460-operates during the third impulse. The proper printer magnets will now beenergized in the following manner. The operation of relays 460 and 465 connected negative battery to lead 463, thence to the windings of all the magnets 490 and 494, If the armature of relay 480 is closed at its front contact, 490 is energized over battery common lead B. C. If the armature of relay 482 is closed at its front contact, 491 is energized over lead B. C; If relay 4T0 operated during the second im pulse, magnet 492 is energized via 471 and 'f' 472- If relay 450 operated upon] the third impulse, 493 is energized via 451 and453.

Similarly, if relay 455 operated upon the third impulse, magnet 494 is energizedvia 456 and 457.

It is obvious that if a suitable code be adoptedthe printer magnets will assume settings correspond ng exactly to the positions of the contact members of the tape trans Symbols C and O appliedin the column transmitter tape indicate closed and 'open respectively With respect to the hve contact members 310 to 815 inclusive. The symbols U and D applied'in the column relay setting are intended to indicate the operated position and the down, released or normal position of the relays 450, 455,'and 470 respectively. The particular impulse of the cycle (that is first, second or third) is indicated in the column impulse transmitted.

The operation ofrelays 460 and 465 like- Wise completes a circuit to energize magnet 486. This magnet advances the, recording mechanism .to start the printing cycle.

A circuit is also closed for relay 484 which operates closing its armature and front contact to complete a circuit to actuate relay 465 as follows: positive battery, lead B. (l, 485, right hand winding 465 to negative battery. telay 465 now transfers its armature 467 from its front contact 466 to to its back contact 467 and the apparatus is now ready for the first impulse ofthenext.

cycle.

With a sin-unit code, i. e. using the dotted elements of Figs. 3 and 4,"the operation for the first and third impulses is identicalwith that described above. For the SQCODQ impulse, the apparatus functions as follows:

The transmitted frequency is under control of contacts '312322, and 815825. (Fig. 8). Assume the code to be so arranged that for sixteen combinations the contact 315 is closed and the contact 312 is open. The contact 315 is, of course, open for thirty-two combinations, during sixteen of which the contact 312 is closed, and during the remaining sixteen combinations of the thirty-two it IS open. This arrangement obviously gives one of three frequene 475, it will be found that the respective armatures of these relays will in all three cases reproduce the settings of transmitter; contacts 312 and 315 (Fig. 3), discussed in.

the preceding paragraph.

The settingof armature 477 of relay 475 will, of course, be transferred to record ng magnet 495 during the third impulse.

The following is a suitable code for the arrangement just described.

Transmitter tape Relay setting (Fig. 3). '(Fig. 4). Impulse Frequency transmitted.

O 0 D D First. 0 v 0 U D First. 0 O D U First. 0 G U U First.

O O D D Second. C O U D Second. 0 O D U Second.

O O D D Third. O O U D Third. 0 VC D U Third. G O U U Third.

The symbols C, O, U, D, refer, as usual, to therespective closed, open, up and down positions of the transmitter (50 1-.

tacts and relay armatures.

TWhat is claimed is:

v1. In a signaling system for transmitting characters in accordance with a] prearranged code, means for recording the characters in succession in codified form, a timing device comprising an interrupter, a circuit including said timing device and. a plurality of impedances constituting a network of variable impedance for generating alternating current impulses, the frequency of each impulse varying with each variation in impedance of the network and the duration of each impulsebeing measured by the timing. device. the variations in impedance of the network being in turn controlled by the record code, and a channel into which the impulses are directed 2. In a signaling system for transmitting characters in accordance with a prearranged code, a standard tape transmitter machine for recording the characters in succession in an interrupter, a circuit including said'timing device and a plurality of impedances constituting a network of variable impedance. for generating alternating current 1mpulse's, the frequency or" each impulse vary ing with eachva 'iation in impedance of the network and the duration of each impulse being measured by the timing device, the variations 7 in impedance of the network beingin turncontrolled by the recorded code, and a channel into which the impulses are directed.

3. In a signaling system for transmitting characters in accordance with a five unit code, means for recording the characters in succession in the form of a five unit code, a

timing device comprising aninterrupter, a c1rcu1t including said timing device and a .pluralityoif impedances constituting a network of variable impedancefor generating alternating current impulses, the frequency of each impulse varying with each variation in impedance of the network and the duration of each impulse being measured by the timing device, the variations in impedance of the network being in turn controlled by i the recorded code, and a; channel into which the impulses are directed.

4-. In a signaling system for transmitting characters in accordance with a prearranged code, means for recording the characters in succession in codified form, a timing device comprising an interrupter, a circuit including said timing device and a plurality of impedances constituting a net work of variable impedance for generating alternatingcurrent impulses, the frequency of each impulse varying with each variation in impedance of the net work and the duration of each impulse being measured by the timing device, the variations in impedance of the network being in turn controlled by the re'cord pulses, the frequency of each impulse vary-' ing with each variation in impedance of the network and the duration of each impulse being measured by the timing device, the variationsin impedance of the network being in turn controlled by the recorded code, a receiving station, and a channel leading to the receiving station into which the impulses are directed. v

6. In a signaling system for transmitting characters in accordance with a. live unit code, means for recording the characters in succession in the form of a live unit code, a timing crevice comprising an interrupter,a circuit including said timing device and a plurality of impedances constituting a networkoi variable impedance for generating alternating current impulses, the frequency of each impulse varying with each variation in impedance of the network and the duration or each impulse being measured by the timing device, the variations in impedance of the network being inturn controlled a channel leading to the receiving station into which the impulses are directed.

7. In a signaling system a sending station for transmitting characters in accordance with a prearranged code comprising means for recording the characters in succession in codified form, atiming device comprising an interrupter, a circuit including said timing device and a plurality of impedances constituting a network of variable impedance l'or generating alternating current lmpulses,

the frequency of each impulse varying with each variationin impedance of the network and the duration of each impulse being measured by the timing device, the variations in impedance of the network being in turn controlled by the recorded code, areceiving station, a channel between the sendingand the receiving stationsinto which the impulses are directed, means at the receiving by the recorded code, a receiving station and station selectively responsive to each impulse, a register translator whose setting is controlled by the impulse responsive means, and means controlled bythe register translator for recording the character represented by the setting of the registertranslaton 8. Ina signaling system a sending station for transmitting characters in accordance with a prearranged code comprising a standard tape transmitter machine forrecording the characters in succession in codified form,

a timing device comprising an interrupter, a circuit including said timing device and a plurality of impedances constituting a network of variable impedance for generating lternating current. impulses, the frequency of each impulse varying with each variation of the impedance in the network and the duration of each impulse being measured by the-timing device, the variations in impedanceof the network being in turn controlled by the recorded code, a receiving station, a channel between the sending and receiving stations into which the impulses are directed, means at the receiving station selectively responsive to each impulse, a register translator whose setting is controlled by the im-,

pulse responsive means, and means controlled by. the registerv translator for recording the character represented by the setting of the register translator. l

9. a signaling system a sending station for transmitting characters in accordance with a five unit code, means for recording thegcharacters in succession in the form of a five unit code,ra timing device comprising an interrupter, a circuit including said timing device and arplurality of inipedances constituting a network of variable impedance for generating alternating current impulses, the frequency ofeach impulse varying With each variation in impedance of the network and the duration of each impulsebeing measured by the timing device, the Variations in impedance ofthe network being in turn controlled by the recorded code, a receiving station, a channel between the sending and receiving' stations into WlllChthB impulses are directed, means at the receiving station selectively responsive to each impulse, aregister translator Whose setting is controlled by the impulse responsive means, and means controlled by the register translator for recording the character represented by the setting of the register translator.

NILS A. ROBINSON. 

